Two-ply cinematograph positive film



June 26, w28. www@ J. E. THORNTON v TWO-"P'LY CINEMATOGRAPH POSITIVE FILM Filed May 4, 192s 2 sheets-sheet v l nllllllllllllllllllllllllllllIlIlllllllIllllllllflllllilllilllilfll Junez, 1928. mmm@ J. E'. THORNTON TWO-FLY CINEMATOGRAPH POSITIVE FILM Filed May 4, 192e 2 sheets-sheet 2 l Figli.

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/AIV/ Patented dan@ 26, M28.

urry JOHN EDWARD THORNTON, OF WEST HAMPSTEAD, LONDON, ENGLAND.

TWO-FLY CINEMATOGRAPE POSXTIVE FILM.

Application led May 4, 1926, Serial No. 106,730, and in Great Britain March 181926.

This invention relates to an improved cinematograph two-color film-of positive pictures,l of the type built up from two thin films cemented together back-to-back, the images upon one outer face of the completed film being of orange-red coloring and those upon the opposite outer face of blue-green coloring, one of the images being reversed in relation to the other; and to an improved process of producing such film without the use of silver sensitizing; without the use of developing, hardening, bleaching and fixing baths which are necessary for silver; without having to color ori-dye the two sets of images after printing; without having bare margins thinner than the rest of the film to prevent creeping-and mixing of the two dyes; without forming a softened weakened hinge longitudinally of the strip to enable it to be folded; without folding the strip; without the use of methyl-alcohol te soften the Celluloid backs; and without need for cementing the two thin films together before development; all of which features are used in the production of another two-color film of the two-ply type, but are not used in the present invention.

' The characteristic features of the present invention comprise the following, used or operating in combination (1) Ready-colored film-material, of

(2) Double-Width, with two parallel colored stripes,

(3) Sensitized with bichromate or other slow-printing salts;

.parallel stripes of orange-red and blue-green colored colloid, carried upon and amalgamated by means of an adhesive substratum with a double-width support of transparent Celluloid orl like waterproof material, the thin film having a thickness approximately half the ultimate `thickness of a completed film-positive, the colloid layer being sensitized with bichromate or other slow-printing l salts. This film-material is printed by exposure from the back through the celluloid support andv through a suitable printingclich of negative character, to produce a posit-ive with relief-images by simple development with hot water or other suitable solution alone. None of the 4baths and solutions necessary With silver-printing are used or required, one treatment being all that is necessary to develop and complete the twocolor print.

The colloid may be gelatine, glue, fishglue, albumen, or a mixture thereof, and the coloring matter may comprise pigments or dyes, but dyes are preferred and are suitably mordanted to prevent their washing out.

The film-material is printedfdeveloped (4) Complete development by one opi/and dried whilst in its double-width form,

without after which it is logitudinally severed to form two films that are subsequently cemented together back-to-back to form the completed single-width film-positive.

By the improved process of producing the `film positives With the characteristic features described in the second paragraph hereof, a simpler and cheaper process of manufacture is obtained, and a film-positive of equal if not better quality is produced Vby fewer manipulative operations, than by methods hitherto known and used.

The accompanying drawings illustrate the invention in which drawings :-I

Fig. l, shows a strip of ready-colored double-width sensitized film of half stand'- -ard thickness, `orange-red on onel half and blue-green on the other half.

Fig. 2, shows the same film perforated before printing with onehole for each picture component for registration purposes only while printing, assembling, and cementing.

Fig. 3, shows a double width negative strip having the conventional design of a square, the image for one negative beine' reversed. The negative on the rightV reprev sents orange-red and that on the left bluegreen.` riwo single-width negatives may be used side by side insteadI of one doublewidth.

Fig. Zl, shows -the positive as it would appear after printing with the picture images alone, if developed without also printing the margins. i-

Fig. 5, shiiwsthe same positive after receiving a second exposure 'to print the margins so'that the latter wil'be rendered ris f The substratum' 2, Trio-on insoluble and appear solid b ack aiter development.

Fig. 6, isa. section through the developed positive, the'images being represented by the ycolloid graduations and the margins by the `solid black portions.

Fig. 7, represents the two pictures afterV the double-width film has been severed longitudinally and the two halves superimposed, registered by the two registration holes, and cemented. j,

Fig. 8, shows the finished iilm after peroratlon with the eight' traction holes.

Fig. 9, is a perspective view of the two films being brought together for the'cementing operation, the end of the figure showing the two Celluloid centres, the two relief l of an inch.

The temporary pa, er reinforcement -,UZW of an inch, but in t e various figures the ,printed colloid-relief layer is shown enlarged out of proportion to the thickness of the Y, other layers for sake of clearness.

Film-material amel sensitizing process. The film-material may be of the type comprising a celluloid layer, a substratum layer,

a colored colloid layer,/ d a temporary reinforcing strip Qgf pap r l attached to its gemelo colored face for giving extra strength to the film during the printing and developing recesses, as described in my Specification berial No.y 35,7 61, June 8th, 1925; and illustrated in Fig. 410; or it may be of the nonreinforced ordinary type film-material comprising a Celluloid layer, a. substratum layer,

'and a colored colloid layer, as .described in my specification Serial No. 35,760, J une 8th,

1925. In both forms the film-material is provided with two parallel stripes of colloid ready colored with the correct pair of colors (Fig. l and with the correct quantity of color in each, that will produce a finished picture having properly balanced and proportioned colors Without any need for the usual ltroublesome dyeing of therv images or adjusting the colorings by the printer after the film has been exposed and developed, which are necessary with other processes. These two colors are orange-red and bluegreen, but instead red and blue may be substituted upon condition that after the film has been developed a yellow dye is applied all over the film in order to.couvert the red images into orange-redY and thel blue images into blue-green.

IThe film'1material is preferably sensitized with a bichromate salt, such as a solution of ammonium, otassium, or lsodium bichromate of the strength common in bichromate printing, which can be varied according to intensity of the printing-clich.

Other suitable sensitizing salts may be used, for example iron, uraniumI and possibly others, but bichromate are preferred,

and the term sensitized for slow printing.

used herein means and includes the use of 4any sensitizer incapable of bein affected byV an instantaneous exposure,`as istinguished from silver salts which are necessary for rapid printing.

\ Negatives onprinting clichs.

The negatives used for print-ing may be either the original negatives or printingclichs reproduced therefrom, and the two component'negatives or clichs may be formed as two parallel lrowsupon a doublewidth strip, or two separate single-width negative-strips may be rused side by side.

Printing.

y Owing to the longer exposure necessary for slow-printing material sensitized with bichromate, iron, or other metallic salts asy compared with silver salts, (the ratio being'` Y about 500 to 1 compared with standard practice) printing is effected by "exposing the film under, a suitable printing-clich to. a light ofpmuch greater intensitythan usual tube, a mercuryvapour quartz-tube, a tung- .sten-arc,- or any equivalent type of lamp givlng-a light of the requisite stability and in- -with silver,A such as a mercury-vapour glassi I denti/ying components.

, To guard against any possibility of mistakes in correctly assembling the two component images of the same picture, identification numbers may be printed on both films.

Margins of full strength and thickness.

In other inventions where images are formed in relief a characteristic feature has been that the margins of the film were bared and freed from gelatine after development and before coloring, which had the effect of reducing the thickness of the finished cemented film at the perforated margins, thus considerably reducing the strength of the film at the Very place where it most needed strengthening. These bare margins formed dams, which prevented creeping and mixing of the two dyes during the process of dyeing the two sides of the printed and cemented film. i

A feature of thepresent invention is that this objection is removed b leaving the full thickness of gelatine covering both margins of both component strips, so that when the two films are cemented together the completed film-positive will have full thickness and full strength at the two margins where most needed. This is rendered possible bccause it is not required to dye the two sides of the print after completlon as they are already colored.

In'the ordinary course of printing films of the relief type the margins are coveredby opaquerparts of the printin -cliche', and receive no exposure to insolu lize them, and therefore dissolve away during the hot water development. But in the present invention thtl 1 margins are iven a separate and very complete exposuI/ek to render them completely insoluble, by exposing them to the fill? l printing lamps in such manner that the already exposed image parts are protected by an opaque covering mask and the margins are left uncovered and exposed to the full light of the lamps, thus producing printed margins which on dvelopment remain solid, insoluble, and of full thickness (see Fig. 5).

A characteristic feature therefore of this invention is that the margins of the printed n n Developing.

In another invention where images have' been produced in relief thel usual standard formed in a sensitive gelatino-slver layer bya short exposure to an ordinary filament lamp, then developed with a developer such as pyro to harden the gelatine in contact withD the silver grains, then'bleaching the reduced silver back to the form of silver salt by means of potassium ferro-cyanide, then xing out the silver salts with ordinary sodium hyposulphite, and finally etching off the soft gelatine with hot water. rIhe two images were -afterwards dyed separately.

In my improved film and process I cut out several of these operations and much of the cost, by using the ready-colored colloid which is sensitized without `silver in the .way already described.

After exposure development becomes a verysimple process, consisting only| in dissolving and washing away/ the colored colloidl that has not-been rendered insoluble by the action off light, thus leaving behind relief-images consisting of colored colloid alone, This developing process may be carried out by a machine which passes the film through a succession of baths or under airdriven sprays of a solution having a solvvent action upon the colloid. The solvent can be varied according to the colloid used. For gelatine, hot water or a cold solution of bichromate can be used. For albumen or fish-glue, cold water can be used.

Development is now complete. No other operations are necessary. No subsequent dyeing of the images is required. The film is therefore dried and is then ready for the cementing operations. f

The entire operations of developing and'.

drying may be eected by any suitable type of machine', one convenient form being that described in mygspecification No. 1,173,898;

Uementz'ng after developing and finishing.

. In other inventions where images are formed in relief a characteristic feature hasl been that the two films were cemented together back-to-back (cellulose-to-cellu'lpse) immediately after printing and before development, in order thatthe images upon opposite sides of the central support could be del3nt in the present invention the two films are printed, developed, washed, finished, and dried whilst in their double-width form, and are not severed, superimposed and cemented until the whole of these several operations have been completed. This method presents many advantages in manufacture, one of which is that the wet prints are not injured upon their faces by contact with the numerous sprockets and other mechanism of the developing machine, but on the contrary are maintained face outwards with only the -back of the'celluloid support in contact withy practice was followed, the prints being the machinery until the last printing and develope-d simultaneously in the hot-water bathf" velopng operation has been finished and the film-images dried.

Poodaoo'og oa/tooo zoogo'todo'ooz woolooooog or folding.

ln another invention where two sets of 4images have been printed upon a doublewidth film, the film has been first longitudinally folded. and doubled over upon a line midway between the two sections and then passed .through a perforating machine which punched holes throughl the double thickness. The film was then unfolded and laid as flat aspossible in order that it could be -printed by contact with the printing clich. Nextfit was again folded and cemented celluloid-tocellu loid prior to development, and finally the folded edge was cut away by a trimming machine. The objections to such a system are that the filmmaterialneeds toJbe wider to allow for trimming, and has to be reduced in thickness at the fold lo "the application of a partial solvent in/or er to make the lmkmore pliable at the hinge, so that it can be folded more sharply, and also to enable it to be refolded or unfolded readily. Thisprocess has to be carried out whilst the lm is sensitive, and before'iprinting; and the treat ment of sensitive lm in this manner is ob- ]ectionablein manyl ways as well as rendering the film liable to distortion owing tol the solvent-produced hinge.

lln the present invention none of these objections apply, because'the hlm is {neverfolded but is perforated, printed, developed,

, treated `and dried and also longitudinally severed whilst in its original flat condition, and the two sections are always true to width, need no trimming, are without any liability to distortion, and the perforations are capable of accurately superimposing and registering.

Separate registration and traction perforatz'ons.

The perforations may comprise the usual four holes per marigin per picture, which means sixteen holes or the pair. But ll prefer to perforate the film before printing with only one hole per complete picture for registration purposes only (see Fig. 2)... This means that two adjacent holes are formed in the central margin of the double-width film betweenl the two rows of section pictures, one for each picture-com onent, and

when the two severed single-wi th films, are

' superimposed and cemented together these two holes coincide in accurate` register 'and' form only one hole .in one margin of the compleY picture. The'unitedstrip is next passed thnough a perforating machine which punches the set of eight holes per picture for traction purposes, four in each margin, using the hole already made as allpilot holel from romero which to work in positioning the remaining holes. This pilot hole may forni one of the set of eight. Any other desired number of holes or type of perforations may be used instead of the usual standard eight. This syst/em is described in my specification of application Serial No. 66,605 filed November-2, 1925, and is particularly well suited for use in the form of film comprising the present invention.

U11-ting byteoolsZow-drying thin layers of cellulose.

After, printing and finishing the doublewidth film is slit into two strips as aforesaid 'and these are next united to forma single strip, with its two setsl ofiimage-s located upon its two opposite faces, by lcenie'nting the two thin strips lback-to-back (cellulose-tocellulose). t

Tt is preferred not 'to slit the lilm until this last operation of cementing, and prefl erably by a rotary slitting knife which effects the operation immediately before cementing, so that expansion and contraction will be uniform for both sections up to this last stage.

Tn other inventions it has been proposed to unite two celluloid-films by softening their backs with methyl-alcohol, in order to eifect a quick-union by employinga solvent that will speedily evaporate. lt is well-known by ointing l portion of ingavheavy solvent that will not dry too rapidly.

. The cement is preferably applied to the backs of the two films (Whilst they are suitably supported and carried) by means of` spreading knives, scrapefrs, or rollers that will apply an extremely thin measured layerl of definite thickness of the thicknonsflowable paste-like cement-compound. Thus a lll@ separate layer of the'cement is first laid upon f the backs of the Celluloid or other cellulosic supports. The cement very slowly partially penetrates the cellulose support, becomes amalgamated. therewith as partfof its body, and also forms a superimposed thin llayer or film of cement which remains upon the .surface as a layer of very great adhesivenes'. 125 of the two iilmsare broughtv into contact and pressed' togetherk the two supports be- -come amalgamated, as if only-one strip, by..l ,means of the two extremely thin layers of cellulose paste, which eventually dryhard When therefore the two cement-.coated backs for example the supportis of nitro-'cellulose` (commonly termed Celluloid) the cement is made from dry cuttings of that materia-l dissolved in amyl-acetate, which is a. comparatively heavy slow-drying solvent. If' the support is one of the non-fiam type, compris ing one of. the many varieties of' cellulose` acetate, the cement is made from dry cuttings of that material dissolved in the heaviest solvent of' that material. The particular solvent will vary according to the particular makev of cellulose-acetate used; 'the variety of non-flam forms of cellulose are numerous, and a different slow-dryingy solvent is usually1 necessary with each variety.

It is usual in mixing cellulose cements to incorporate a large proportion of a quicklyevaporating solvent even where a slow-drying solvent is also used; but in this invention I do not use or incorporate any of such highly-volatile solvents but instead rely entirely upon solvents that will slowly penetrate and amalgamate the films and will take considerable time to dry off.

During .application of the thick paste-like cement to the backs of the two films they are suitably held and carried by a cementing registering and uniting machine, which draws the two films from two supply-spools,

'positionsthem with fair accuracy by means of sprocket wheels the teeth of which engage with the perforations of the films; the cement is applied in a'thin layer or film by Scrapers or rollers as the films travel through this machine; and finally the two films are brought into near juxtaposition, and are then engaged by pins which accurately register the twocomponent images, the pins exactly filling'the perforations of the films, and then the two\films are clamped between reciprocating clamping blocks by which they are squeezed together and completely united. Owing to the slow-drying and very adhe-l sive cement used a comparatively light pressure only is needed for this part of the operation.

The mechanical methods of carrying out this part of the process, and machines therefor, are described in my specifications No.

1,169,098 .and of application Serial No.v

756,168 filed December 15, 1924.

One such machine is illustrated in Fig. 11. The stiftl cellulose paste or dope, is contained in .the hoppers A fromwhich it falls through a slit B, the thickness ofithe layer of paste applied to each film being exactly deteri mined by a .scraper knife C controlled by a screw c. Each film is drawn over a spreading table D and the slits B are arranged sufficiently fary back from the point where the two films come together to give the layer of paste time to partially amalgamate with the film supports before they are registered and squeezed together by the blocks E. films pass from the tablesD over the sprocket wheels D1 to the first pair of movable cementing blocks E which are provided with registrati n teeth and thence to the., final movable @locks lll.

The method of uniting the two films previously described has the advantage that the films tobeunited remain comparatively dry and stout, whereas if' a fi'uid solvent such as methyl-alcohol alone is employed the films become soft and liable to distortion.

The two-color positive-film now complete and ready for exhibiting.

If it is desired to vary the physical condition of the colloid images the film may be passed through a bath containing a very small proportion of glycerine to keep body of the colored colloid more supple and less hard. lOr the bath may contain a. very small proportion of chrome alum to harden the surface. I prefer, however, to apply to the two surfaces of the'completed film an extremely thin layer of a colloid varnish in which the glycerine and /or chrome alum are incorporated. This is effected by passing the finished film through a bath of these combined ingredients, then past air jets which blow ,through the perforations to keep them clear of varnish, and finally drying the finished film.

Summary.

produce a film with strong solid margins of full thickness, without;3 any troublesome weakened fold, with less labour and fewer operations, without waste due to trimming,

with a much better joint, and without the` troublesome operations for dyeing the' two .sides in two different colors after. making The,`

izo'

the two prints, and represent considerable improvement upon the methods hithelrto known and used.

What I claimjas my invention and desireto protect by Let-ters Patent is 1. A two colour posltive cinematograph V'film comprising in com nation twosupports of cellulose of the exactwidth of the film, two substratums thereon, two layers of ready-coloured colloid.,- one orange-red and.

the vother blue-green9 two relief images one on each colloid layer, two applied layers Jof cellulose paste between f the A cellulose supports and by which they are joined, and a marginn at each edge formed of the printed colloid to the full thickness of the film material, the cellulose supports being disposed between the two printed colloid layers. '2. A two-colour positive 'cinematograph film comprising in its construction two trans'- parent supports of the exact width of the film, a layer of slow drying stiff cellulose c ement paste by which the supports are joined together, a layer -of colouredy colloid with images printed in relief in bichromate salts on each support, and insoluble solid margins at each edge formed of the printed colloid to the full thickness of the film material.

3. The method' of producing a two-colour positive cinematograph film which consists in utilizing a transparent support coated with two stripes of dierently coloured colloid one coloured orange-red and the other bluegreen sensitized with hichromate salts printing thereon images in. relief and printing the margins adjacent to the images to renderv them'insoluble and solid of the full thickness of the film, developing and linishing the images severing the support longitudinally into two strips the exact width of l i,ereero the film and cementing the supports together with a layer of cellulose aste.

. 4. rlhe method-of pro ucing a two colour printing the margins of sensitized colloid to` positive cinematograph lm as in claim l by produce solid insoluble margins of full thickness equal to the `original lm.

45. 'llhe method of producing a two colour positiyefcinematogra h film which consists 1n prmting and pro ucing images in relief upon a? double width transparent support in L two parallel stripes of di'erent coloured colloid sensitized with bichromate salts, submitting the margins at each side of the images to light to renderI themy insoluble severing the support longitudinally into twol strips of exact width for the film and super-`vv imposing them upon two layers of cellulose paste by which they are unitedback to. back.

,6. In the production of a two colour positive cinematogra h film as in claim. l sub# jecting the margins to a further exposure to -li'ght to render them insoluble and at the same time protecting the previously exposed picture portions of the film during the-sub sequent exposure by a covering maskwhich does not cover the margins.

ln testimony whereof l have hereunto set my hand.

Jona EDWARD Thornton.d 

